s, great variety of, in many forests, 36

Trimen, Mr., on butterfly deceived by its mimic, 245
on mimicry, 247

Tropical animals, why brilliantly coloured, 299

Tropics, no proof of lower temperature of, 369

Tropidorhynchi mimicked by orioles, 263

Trumpeter, 93

Tumblers, 91

Turbits and owls, 91

Tylor, Mr. A., on _Coloration in Animals and Plants_, 285

=U=

Ungulates, origin of feet of, 423

Use and disuse, effects of, overpowered by natural selection, 435

Useless characters, 131
not specific, 132

Useless specific characters, no proof of existence of, 141

Utriculariae inhabiting bromelias, 118

=V=

Vanessa callirhoe, small variety in Porto Santo, 106

Variability of the lower animals, 42
of the Foraminifera, 43
of sea-anemones, 43
of land mollusca, 43
of insects, 44
of lizards, 46
of birds, 49
of primary wing-feathers, 51
of wings and tail, 53
of Dolichonyx oryzivorus, 55
of Agelaeus phoeniceus, 56
of Cardinalis virginianus, 58
of tarsus and toes, 60
of birds in Leyden Museum, 61
of Sciurus carolinensis, 67
of skulls of wolf, 70
of skulls of a bear, 72
of skulls of Sus cristatus, 73
of plants, 76
of oaks, 77

Variation, Lyell on, 4
in internal organs, 66
the facts of, 83
proofs of generality of, 85
of vegetables and fruits, 86
of apples and melons, 87
under domestication accords with that under nature, 100
coincident not necessary, 127
and heredity, problems of, 410
Professor Geddes's theory of, 428
the cause of, 439

Variations of flowers, 88
of domestic animals, 88
of domestic pigeons, 89
conditions favourable to production of, 98
beneficial, 143

Varieties, importance of, 41
of same species adapted to self or to insect-fertilisation, 330

Vegetables, variation of, 86

Vegetation and reproduction, antagonism of, 428

Vertebrata, mimicry among, 261
geological succession of, 405

_Vestiges of Creation_, 3

Viola odorata, 2
canina, 2

Violets, as illustrating species, 2

Von Buch on species, 6

=W=

Wallace, Dr. Alexander, on absence of choice by female moths, 275

Ward, Mr. Lester F., on progressive development of plants, 398

Warning coloration, 232

Warning colours of marine animals, 265

Wasps and bees, mimicry of, 258
poisonous with warning colours, 287

Water-cress, chokes rivers in New Zealand, 24
driven out by willows, 24

Water-ouzels, probable or